Future distribution transformers will be smart service nodes

Project news

The rapidly advancing energy transition and electrification of society will change the service models within the electricity network. For example, electric cars and solar power challenge the low-voltage network and the operation of distribution transformers. In turn, fluctuations in electricity prices have increased people’s interest managing their own electricity use and in small-scale generation as well as local energy communities. These needs can be met by developing distribution transformers into smart service nodes for local communities.

Picture: Externally maintained transformer / Caruna

Local energy communities offer people new ways of participating in the energy transition. The activities of these energy communities and participation in flexibility markets can be facilitated by developing distribution transformers.

– A solution at the distribution transformer-level is definitely an interesting area of development, as it helps to tie together customers and the transformation of the system. In addition to technology, new service models will be needed, which creates opportunities for completely new business, says VTT’s Research Professor Kari Mäki.

New solution would combine small-scale generation and energy storage

VTT is involved in the STRATA project, which aims to develop distribution transformers into smart service nodes. The aim is to combine local electricity generation, energy storage and, for example, quick charging of electric cars and smoothing of charging peaks. The solution would also provide access to local DC networks.

Smart service centres can be used to integrate the flexibility of household consumption into the local control and optimisation system. For this purpose, wireless and cost-effective data transfer connections to the service node will be implemented in households.

Developing a prototype of a smart transformer

STRATA project is an European ERA-NET Smart Energy Systems initiative involving partners from Finland, Scotland and Germany. VTT coordinates the project, and also MSc Electronics, THT Control and Caruna participate from Finland. Other partners include University of Strathclyde, AMPX Limited and Scottish Power from Scotland, as well as Fraunhofer IEEE, Smartrplace, Städtische Werke Netz+Service and EEBUS from Germany.

Together, the partners are implementing a concept and prototype for a new type of smart transformer enabled by latest digitalization and power electronics technologies. The solution will be studied in use-cases based on participating DSOs’ distribution networks and the need for changes caused by the energy transition. The idea is to pilot it both at research environments and in real DSO networks.

– The green transition and the increasing electrification of society pose new challenges to electricity networks. A smarter network can be managed in a more versatile way, while at the same time giving consumers new opportunities to influence their own electricity and energy use. The smart transformer will enable a more flexible implementation of different energy communities and a more efficient utilisation of renewable generation. Smart transformers will also accelerate the deployment of energy storages and flexible solutions, says Innovation Manager Verneri Kohonen from Caruna.

The results of the project offer new tools for designing the distribution network and making better use of energy communities. The results promote the objectives of renewable energy and electric transport in practice.


The three-year STRATA project (Smart Transformation for Resilience And community services Through digitAl grid layers) is part of the European ERA-NET Smart Energy Systems programme. The project is supported by national funding agencies Business Finland, Scottish Enterprise and German Federal Ministry for Economic Affairs and Climate Action / Forschungszentrum Jülich.

Kari Mäki
Kari Mäki
Research Professor
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